How do you think they must have felt when Peter told them that the same Jesus they had crucified, was raised from the dead by the same God they claimed to serve? There was no way they could deny that a miracle had been performed, because the man that was healed was standing before them. They had seen him every day at the gate begging.
In their hearts they knew they had no choice but to let Peter and John go. They commanded them not to speak in Jesus' name again and let them go. What did they do? They went out and spoke the word with boldness, even though it could have meant them going to prison. They continued to preach the same as before.
Why did these men seem to have so much power upon their lives? What was so different about them? Absolutely nothing, except they took Jesus at His word. Jesus told them that they could go out and perform miracles and because He told them they could, they believed Him. We have the same power available to us today. All we have to do is take Jesus at His word and GO!